The present invention relates to a method of synthesizing nanofibers, and in particular silica nanofibers.
High performance fibers are of special interest in applications involving lightweight materials, armored materials, and materials adapted to withstand extreme environments. In the past five decades, various high performance fibers have been synthesized and commercialized. These fibers include silica fibers, carbon fibers, and polymer fibers. High performance fibers are generally characterized by tensile strength, weight, chemical reactivity, production cost, and the availability of raw materials. The following table provides a general overview of many such properties of various high performance fibers, with theoretical values illustrated in parentheses:
High StrengthPropertySilicaCarbonPolymerSteelTensile Strength10 (30)10 (100)3.52.8(GPa)Cost ($/lb)113101Density (g/cm3)2.51.81.57.8TransparencyYesNoNoNoThermal Stability1200-16001600-2000150700(° C.)
As shown in the above table, existing carbon fibers have high tensile strength (10 GPa) and low reactivity, but energy intensive, time consuming, and highly expensive synthesis and low recyclability has limited their use to high-end applications. Similarly, polymer fibers are limited by their low tensile strength, degradability, and high cost. Steel fibers are inexpensive but weight and low tensile strength is a disadvantage. Among these high performance fibers, silica fibers have gained a considerable interest because of the potential for 1) large scale production, 2) an abundance of precursors, 3) low manufacturing costs, 4) a 30 GPa theoretical tensile strength, 5) transparency, and 6) easy recyclability. Accordingly, there remains a continued need for improved manufacturing methods for the scalable production of silica fibers, including nanofibers, across a range of applications and operating conditions.